The development and incentives for the use of renewable energy is a key component of many governmental political strategies. Americans alone consume more than 20 million barrels of oil a day. Currently, the United States imports more than two thirds of the oil it utilizes. Ethanol manufacturing from corn is a subject of great interest at many levels of government. The main drawback of modern ethanol technologies is the neglect of additional value-added products that can be successfully produced parallel to ethanol manufacturing. One of the typical by-products, dried distillers grains and solubles (DDGS), may be sold as animal feed, but is not usually considered an economically viable by-product as its nutritional quality and price is not competitive with conventional soybean feed in many parts of the country. The DDGS also has a short shelf life, making it difficult to market as a feed product. Another undesirable consequence of biofuel production is the air pollution associated with the drying of distillers grains. Most conventional processes use a hot stream of air to dry the distillers grains, which is then vented to the atmosphere causing bad odors near the facility.
Biodiesel refers to mono alkyl esters of long chain fatty acids derived from vegetable oils or animal fats. Biodiesel is a promising alternative fuel source suitable as a diesel fuel or diesel fuel lubricity additive because it is biodegradable, non-toxic and has low emission profiles as compared to conventional fuels. However, high raw material and processing costs have limited the widespread use of biodiesel.
The most common method of producing biodiesel is the base-catalyzed transesterification (or alcoholysis) of triglycerides, such as vegetable oils and animal fats. The transesterification reaction involves reacting the triglyceride with an alcohol to form fatty acid esters and glycerol. The reaction is sequential wherein the triglycerides are reduced to diglycerides, monoglycerides and then to glycerol with ester liberated at each step.